Method and apparatus for tamping fibrous material



Aug. 23, 196 w. w. THOMPSON 3,

METHOD AND APPARATUS FOR TAMPING FIBROUS MATERIAL Filed Aug. 11, 1961 2 Sheets-Sheet 1 IN V EN TOR.

w 754 n/ THOMPS N A TTORA/EYS Aug. 23, 1966 w. w. THOMPSON METHOD AND APPARATUS FOR TAMPING FIBROUS MATERIAL Filed Aug. 11 1961 2 Sheets-Sheet 2 h E z a a n M 1 H & z mum M .M a MP Z. mm W a M m ia mff ATTORIVE'VG United States Patent 3,267,972 METHOD AND APPARATUS FOR TAMPING FIBROUS MATERIAL Walter W. Thompson, R0. Box 627, Hazlehurst, Ga. Filed Aug. 11, 1961, Ser. No. 130,926 6 Claims. (Cl. 14112) This invention relates to a method and apparatus for tam-ping fibrous material into the open cells of a spacing core such as paper honeycomb. The method and apparatus for the present invention are particularly directed to met the requirements for tamping fiberglass wool into the paper honeycomb cells of a spacer core employed between light gauge sheet sheet pans assembled in the construction of acoustical ceiling panels.

In such construction, the honeycomb spacer core is preferably bonded to each of the interior pan faces in order to impart structural rigidity to the panel so that it is important in filling the honeycomb cells with the sound absorbing fibrous material, such as fiberglass wool, that the fibers be fully contained within the cells without extending across the edge surfaces required to be bonded to the metal pan elements. It is also necessary that the fibrous material be packed to a greater density than may be achieved by simply spreading or blowing the fibrous material onto an open honeycomb face.

The present method and apparatus developed to meet these requirements are characterized primarily by the use of flexible tampin-g fingers which are adapted to project into the paper honeycomb cells to fill them with and compress the fibrous material, the tamping fingers being repeatedly reciprocated into and out of the cells with sufiicient taper ,to freely release from the fibrous material when withdrawn and suflicient flexibility to avoid damage to the edge structure of the honeycomb core upon contact.

The objects and advantages of the method and apparatus may be best understood from the following description of a preferred embodiment with reference to drawings showing a preferred form of apparatus wherein:

FIGURE 1 isa side elevation of preferred apparatus embodying and adapted to carry out the method of the present invention;

FIGURE 2 is a sectional end elevation taken along the line 22 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary sectional side elevation showing the penetration of tamping fingers within fiber filled honeycomb core;

FIGURE 4 is a sectional plan view taken along the line 44 of FIGURE 3;

FIGURE 5 is a fragmentary sectional side elevation similar to FIGURE 3 showing the deflection of a rubber finger by contact with the side wall of one of the honeycomb cells;

FIGURE 6 is an enlarged fragmentary sectional view of one of the driving units shown in FIGURE 2; and

FIGURE 7 is a perspective partially cut-away view of one of the acoustical units employing a honeycomb core filled with fiberglass packed in accordance with the present method and apparatus.

Referring to FIGURE 1, the preferred apparatus includes a pair of frame elements 10 and 11, the former supporting bearing blocks 12a, 12b, 12c and 12d having bearings 13 for four transverse drive shafts 14 of which that shown in FIGURE 2 has a pair of sprockets 15 and 16, the former receiving drive from motor 17 through reduction sprocket 18, chain 19, sprocket 20, sprocket 21, and chain 220, and the latter driving chain 22d engaging a similar sprocket on the shaft 14 associated with bearing blocks 12d. A similar drive from the motor 17 is provided for the shafts associated with bearing blocks 12a and 12b, idlers 23- being provided as required for chain tensioning.

Each shaft 14 drives a pair of crank'plates 24 each carrying an eccentric pin 24a engaging a crank arm 25 driving through connecting pin 25 a vertically reciprm cable arm 26 guided by a vertical bearing 27, the lower end of which is provided with a bellows seal 28 which together with the lower end of the arm 26 is connected through spreaders 29 and plate 30 to either end of a transversely extending plate head 31 on the lower surface of which are bonded rubber pads 32 having molded tapered rubber fingers 33 projecting downwardly therefrom, the construction of which is best shown in FIGURES 3 and 5. Such fingers are adapted upon reciprocation of the heads 3'1 to press down and compact fibers 34 within the cells 35 of a honeycomb core spacer unit bonded to a metal pan having a lower surface 36 and upwardly extending sides 37. A series of pans in close proximity pass under the reciprocating heads on a suitable conveying element 38 (the supporting structure for which is not shown). These open pans extend between guides 39 and as stacked against each other substantial-1y cover the conveyor surface in moving from left to right under the reciprocating heads. The heads are positioned to withdraw to a clearance position at the top of every stroke and to cause the rubber fingers to penetrate the cells during the down stroke of each cycle with the lowermost position of the successive heads in the direction of conveyor travel extending to a progressively greater depth in order to effect a progressively more complete packing of the fibers spread across the core in advance of the tamping heads to a final level just below the upper surface of the core.

Upon completion of the tamping operation, a metal cover 41 having bonding material applied to the inner surface thereof is placed over the individual lower pans to effect a completion of the sandwich-assembly with the core securely bonded to both iner pan faces. The completed assembly, with the perforated face inverted to a lower position, forms a panel for an acoustical ceiling wherein sound will enter the perforated face being absorbed and deadened by the fibrous material within the cells of the core. The resulting bonded core spaced skin construction provides considerable strength per mitting the use of extremely thin gauge sheetmetal pans. However, in order to effect proper bonding of the pan member 41 to the adjacent edge surface of the honeycomb spacer core, it is extremely important that the fibrous material be fully confined within the cell structure and not extend over the edges where it would interfere with proper bonding. It is also important that the means employed not damage relatively fragile exposed edges of the core material such as the preferred paper honeycomb.

In a specific case of packing fiberglass wool in an expanded paper honeycomb core bonded to a bottom steel sheet .010" thick wherein the honeycomb is one inch thick and the cells are approximately one inch in diameter and wherein the wool is to be packed approximately four to five ounces per square foot below the top surface of the honeycomb so that when the steel face is applied the wool will not contact the top steel sheet, it has been found that the packing can be accomplished through the use of rubber-like fingers 1% inches long tapered from A inch at the 'base to A2 inch at the tip molded onto a rubber base sheet 4 inch thick in rows /2 inch apart in both directions, plates with finger pads attached being actuated with an up and down reciprocating movement as pans having fiberglass spread across the surface are passed underneath. A rubber hardness in the order of 20 to 25 durometer has been found to provide sufficient flexibility to allow the paper honeycomb to remain undamaged when contacted during the tamping, as by fingers 33a shown in FIGURES 4 and 5, and the taper and flexing effectively prevent buildup of the fiberglass between the fingers. V

The specific machine illustrated has been tested to establish continuing durable effective operation at a reciprocating rate of approximately two hundred strokes per minute without undue deterioration from vibration, wear of the rubber fingers or from glass fibers entering the various bearings of the machine. The fiberglass employed is of a blowing wool short staple inch down texture, and cover plates 48 and bellows seals 28 have been found important to prevent undue wear to the crank bearings from glass particles; in addition, the entire mechanism above the camping heads is enclosed by cover, not shown, to prevent glass fibers from getting into the bearings of the motor, chains, sprockets, and other moving parts.

While a preferred method and apparatus have been described above in detail, it will be understood that numerous modifications might be resorted to without departing from the scope of this invention as defined in the following claims.

I claim:

1. A method for compacting fibrous material into an open faced cellular structure characterized by placing the cellular structure face up on a support structure, spreading the fibrous material onto the open face, and progressively moving the cellular structure along the support structure whilereciprocating a plurality of flexible, su'b cellular sized fingers through the fibrous material from above the uppermost level of the fibrous material to below the uppermost level of the open face of the passing cellular structure, said fingers deflecting upon engagement with the upper edge of a cell of the open faced cellular structure.

2. A method for compacting fibrous material into an open faced paper honeycomb cellular structure characterzied by placing the cellular structure face up on a support structure, spreading the fibrous material onto the open face in a horizontal layer extending above the paper honeycomb and reciprocating a plurality of flexible fingers capable of deflecting upon contacting the upper edge of the paper honeycomb cellular structure vertically through the layer of fibrous material into and out of the cellular structure while providing relative horizontal movement between the reciprocating fingers and the cellular structure.

3. A method for compacting fibrous material into an open faced cellular structure characterized by placing the cellular structure face up on a support structure, spreading a quantity of fibrous material corresponding to the required final density onto the open face in a horizontal layer extending above the cellular structure and progressively moving the cellular structure along the support structure while reciprocating a plurality of flexible tapered fingers through the fibrous material and onto and out of the cellular structure to a progressively increasing depth of penetration as the compacting action continues, said fingers deflecting upon engagement with the upper edge of a cell of the open faced cellular structure.

4. Apparatus for compacting fibrous material into an open faced cellular structure characterized by a plurality of tapered flexible projecting fingers mounted on a reciprocable head, means for reciprocating said head, and means for conveying said cellular structure to a position wherein said reciprocating fingers will penetrate into said cellular structure, said fingers being sufficiently soft, thin and flexible to deflect to either side of the marginal edge walls of a paper strength honeycomb cellular structure upon engagement therewith.

5. Apparatus as set forth in claim 4 including a rubber base pad to which rubber fingers are integrally attached, and a rigid head member to which said rubber base pad is attached.

6. Apparatus as set forth in claim 5 including a plurality of reciprocable heads, each having said rubber fingers projecting from the lower surface thereof, and means for moving said cellular structure progressively under successive heads, the fingers of successive heads in the path of said cellular structure being adapted to penetrate to a progressive-1y deeper level.

References Cited by the Examiner UNITED STATES PATENTS 244,378 7/1881 Clark 14 1-807X 947,548 1/1910 Lind 94-48 1,127,113 2/1915 Thiemann 141-80 X 1,977,851 10/1934 Hepperle 22-187 2,124,588 7/1938 Murch 141-80 X 2,255,344 9/1941 Baily 9448 2,292,733 8/1942 Baily 9448 2,518,223 8/1950 Christiansen 141-80 2,757,845 8/1956 Eut-hi et .al. 141--80 2,936,669 5/1960 Douglass 141-73 X LAVERNE D. GEIGER, Primary Examiner.

J. JACKSON, H. BELL, Assistant Examiners. 

1. A METHOD FOR COMPACTING FIBROUS MATERIAL INTO AN OPEN FACED CELLULAR STRUCTURE CHARACTERIZED BY PLACING THE CELLULAR STRUCTURE FACE UP ON A SUPPORT STRUCTURE, SPREAD ING THE FIBROUS MATERIAL ONTO THE OPEN FACE, AND PROGRESSIVELY MOVING THE CELLULAR STRUCTURE ALONG THE SUPPORT STRUCTURE WHILE RECIPROCATING A PLURALITY OF FLEXIBLE, SUBCELLULAR SIZED FINGERS THROUGH THE FIBROUS MATERIAL TO BELOW THE UPPERMOST LEVEL OF THE OPEN FACE OF THE PASSING CELLULAR STRUCTURE, SAID FINGERS DEFLECTING UPON ENGAGMENT WITH THE UPPER EDGE OF A CELL OF THE OPEN FACED CELLULAR STRUCTURE. 